342 E. B. MATHEWS — MARYLAND AND PENNSYLVANIA PIEDMONT 



syncline whose axis conforms to the general character of the continental 

 structure. Such a geo-syncline would be between the Blue Ridge and 

 Great valley on the north and west and the accumulation of metamor- 

 phosed sediments and igneous rocks on the east. This inference is, 

 moreover, corroborated by the character of the folding where it has been 

 deciphered in eastern and central Maryland. 



The map still further shows that, while the forces at work to produce 

 the Appalachian structure along the Atlantic coast were exerted north- 



Figuee 2. — Sketch of axial Lines for major Structures of the Piedmont. 



west and southeast, the distribution of force in the Maryland Piedmont 

 was very much more complex, since the center of the major curve of the 

 continental structure lies approximately coincident with the city of 

 Baltimore. This fact would seem to indicate that whatever forces were 

 at work in the Maryland Piedmont during the formation of Appalachian 

 structures must have worked on lines radiating from a central point, 

 ■and that if any difference of force along these lines occurred there must 

 have been developed more or le3s torsional stress, and that such torsional 



